Ejection seats have long been known for propelling an aircraft crewmember from a damaged aircraft so that the crewmember can safely deploy a parachute once clear of the aircraft and return safely to the ground. Typically, the deployment mechanism comprises a rocket or a drogue parachute, or a combination of them, which pulls the parachute from a container carried either by the crewmember or the ejection seat. However, once the deployment mechanism has served its function it is highly desirable to discard this mechanism from the parachute.
One reason to discard this mechanism is that it tends to tangle the parachute. Another reason is that the rocket is usually very hot and can swing into and burn the crewmember or the parachute material. A third reason is that discarding the deployment mechanism reduces the mass aft of the parachute and thereby reduces the shock to the crewmember due to the inertial snatch force generated by the complete opening of the parachute.
While there have been numerous prior art attempts at providing an advantageous and efficient discard assembly, they have numerous problems, be they formed as line cutters activated by snub lines or explosive devices. For one thing, these devices tend to weigh a lot and in addition are bulky. Moreover, they tend to work in an unreliable fashion and at unreliable times. In this regard, it is very important for the discard assembly to be activated after the parachute is fully extracted from its container but before it is fully opened in order to reduce the shock to the crewmember as outlined above.
Examples of these prior art discard assemblies are disclosed in U.S. Pat. Nos. 3,433,440 to Stanley; 3,436,037 to Stanley; 3,595,501 to Stencel et al; and 3,726,499 to Stencel.